.nav {
    width: 100%;
    background-color: #333;
    >.nav-center {
        width: 1200px;
        margin: 0 auto;
        height: 40px;
        >ul {
            list-style: none;
            display: flex;
            >li {
                width: 80px;
                text-align: center;
                line-height: 40px;
                &:hover {
                    background-color: #000;
                }
                >a {
                    text-decoration: none;
                    color: #fff;
                    font-weight: 900;
                }
            }
        }
    }
}